The present invention refers to a hearing aid, and in particular to a hearing aid with a switch for controlling the connection to a power source.
Hearing aids of this kind generally include an electronic amplifier connected to the power source e.g. a battery which supplies the necessary energy for allowing the amplifier to boost the incoming sound pressure to an higher outgoing sound pressure. The amplifier includes the earphone providing the signal at the sound outlet port which is in connection with the ear.
In order to prevent a useless current drain and to save energy when the hearing aid is not in use, a manually actuable switch is provided by which the connection between the amplifier and the power source may be interrupted. Such a hearing aid has the drawback that the user may forget to actuate the switch after use so that the battery may run empty especially when leaving the hearing aid in on-position overnight. The same is true when the hearing aid after being turned off is dropped and hits an object which may accidently change the switch to the on-position thereby draining the battery and thus rendering the hearing aid inoperative.
The U.S. Pat. No. 3,227,836 describes an eyeglass frame with an integrated hearing aid which includes a switch in form of a spring-loaded plunger projecting from the side piece of the eyeglass and provided for making or breaking a connection between suitable contacts and thus between the power source and the amplifier. When wearing the eyeglass, the plunger is slid forwardly to close the contacts. When removing the eyeglass, the plunger is returned by the action of the spring so as to open the contacts.
A hearing aid of this kind has the drawback that the spring-loaded plunger exerts during wearing of the eyeglass a force which may result in painful pressure marks on the skin of the user and may lead to changes of the skin. Considering that hearing aids are worn for a prolonged period, the use of such an eyeglass frame is uncomfortable for the stated reasons.
The DE-OS 31 09 049 discloses a hearing aid which includes a manually actuated on-off switch and in addition a magnetic switch responsive to the magnetic field of a telephone receiver or a headset. This magnetic switch acts, however, only in response to magnetic variations when guiding the telephone receiver or headset to the ear but does not control functions of the hearing aid.